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Municipal solid waste management is a paramount activity in modern cities due to environmental, social and economic problems that can arise when mishandled. In this work, the sequencing of micro-routes in the Argentine city of Bahía Blanca is addressed, which is modelled as a vehicle routing problem with travel time limit and the vehicle's capacity. Particularly, we propose two mathematical formulations based on mixed integer programming and we solve a set of instances of the city of Bahía Blanca based on real data. Moreover, with this model, we estimate the total distance and travel time of the waste collection and use this data to analyse the possibility of installing a transfer station. The results demonstrate the competitiveness of the approach to resolve realistic instances of the target problem and suggest the convenience of installing a transfer station in the city considering the reduction of the travelled distance. [ABSTRACT FROM AUTHOR]

The current situation of world’s environmental issues, indicates that not only the man-made environmental damages have not been diminished, but also has given rise to more acute issues such as water and soil pollution, biodiversity loss, ozone depletion, greenhouse phenomena, etc. One of the most prominent effects of urban development on environmental problems caused by solid waste generated in urban areas. Transportation and disposal of wastes are directly connected to public health, and pollution of water, soil and air. Municipal solid waste transfer stations play an important role in waste management systems; however, they have been practically disregarded in most developing countries. Environmental impacts of solid waste transfer station (SWTS) for the relevant options in the north west of Tehran city is the main focus of this study. Environmental impact assessment of these options was performed using two methods: rapid impact assessment matrix (RIAM) and Iranian Leopold matrix (modified Leopold matrix). The rapid impact assessment matrix method provides fast and accurate ways of analysis and reanalysis of specified components. Iranian Leopold matrix chiefly is used for the reorganization of the project impacts in both the building and operation stages. Indoor loading/unloading with establishment of green space around the SWTS was found to be the most pragmatically beneficial option, based on the obtained results from Iranian Leopold and Rapid Impact Assessment Matrices.

• Logical framework for developing efficient MSW management system. • Multi-attribute model for finding suitable locations of MSW facilities. • Inclusion of all relevant environmental, social, economical and technical criteria. Selecting appropriate locations for municipal solid waste (MSW) management facilities, such as transfer stations, is an important issue in rapidly developing regions. Multiple alternatives and evaluation attributes need to be analyzed for finalizing the locations of these facilities. Multi-attribute decision-making (MADM) approaches are found to be very effective for ranking several potential locations and hence selecting the best among them based on the identified attributes. However, conventional MADM approaches fail to find the rankings of alternatives derived from all possible combinations of these potential locations. Therefore, this study presents a two-stage MADM model that also accounts for all possible combinations of locations. This study evaluates economical, environmental, social and technical attributes based on realistic conditions of the study area, i.e. , Nashik city (India). The results provide the ranks of all possible combinations along with their probabilities of rank reversibility. The mean and standard deviation of the relative closeness are further evaluated for the top-ranking locations under distinct schemes. The present study will help stakeholders in finding suitable locations for MSW management facilities while considering economic, environmental, social and technical attributes. [ABSTRACT FROM AUTHOR]

Solid waste management (SWM) is among the poorly rendered services in developing countries' limited resources, increasing population, rapid urbanisation and application of unscientific, outdated systems leads to inefficiency. Lack of proper planning and inadequate data regarding solid waste generation and collection compound the solid waste management problem. Given the large number of available waste management options and the inter-relationships among them, identifying SWM strategies that satisfy economic or environmental objectives is a complex task. The paper integrates the effects of transfer station(s) to a mathematical model developed for a municipal Integrated Solid Waste Management (ISWM) system and focusses on the effect of inclusion of transfer stations on the overall efficiency and cost-effectiveness of an ISWM system. The model then serves as decision support tool to evaluate various waste management alternatives and identifies the least cost optimal combination of technologies for the collection, transport, treatment and disposal of waste. The constraints include those linking waste flows and mass balance, processing plants capacity, landfill capacity, transport vehicle capacity and number of trips. The linear programming model integrating different functional elements was solved by LINGO optimisation software and various possible waste management options were considered during analysis. [ABSTRACT FROM AUTHOR]

The objective of this work was to develop an optimization model to minimize the cost of a collection, haul, transfer, treatment and disposal system for infectious medical waste (IMW). The model calculates the optimum locations of the treatment facilities and transfer stations, their design capacities (t/d), the number and capacities of all waste collection, transport and transfer vehicles and their optimum transport path and the minimum IMW management system cost. Waste production nodes (hospitals, healthcare centers, peripheral health offices, private clinics and physicians in private practice) and their IMW production rates were specified and used as model inputs. The candidate locations of the treatment facilities, transfer stations and sanitary landfills were designated, using a GIS-based methodology. Specifically, Mapinfo software with exclusion criteria for non-appropriate areas was used for siting candidate locations for the construction of the treatment plant and calculating the distance and travel time of all possible vehicle routes. The objective function was a non-linear equation, which minimized the total collection, transport, treatment and disposal cost. Total cost comprised capital and operation costs for: (1) treatment plant, (2) waste transfer stations, (3) waste transport and transfer vehicles and (4) waste collection bins and hospital boxes. Binary variables were used to decide whether a treatment plant and/or a transfer station should be constructed and whether a collection route between two or more nodes should be followed. Microsoft excel software was used as installation platform of the optimization model. For the execution of the optimization routine, two completely different software were used and the results were compared, thus, resulting in higher reliability and validity of the results. The first software was Evolver, which is based on the use of genetic algorithms. The second one was Crystal Ball, which is based on Monte Carlo simulation. The model was applied to the Region of East Macedonia – Thrace in Greece. The optimum solution resulted in one treatment plant located in the sanitary landfill area of Chrysoupolis, required no transfer stations and had a total management cost of 38,800 €/month or 809 €/t. If a treatment plant is sited in the most eastern part of the Region, i.e., the industrial area of Alexandroupolis, the optimum solution would result in a transfer station of 23 m 3 , located near Kavala General Hospital, and a total cost of 39,800 €/month or 831 €/t. A sensitivity analysis was conducted and two alternative scenarios were optimized. In the first scenario, a 15% rise in fuel cost and in the second scenario a 25% rise in IMW production were considered. At the end, a cost calculation in €/t/km for every type of vehicle used for haul and transfer was conducted. Also, the cost of the whole system was itemized and calculated in €/t/km and €/t. The results showed that the higher percentage of the total cost was due to the construction of the treatment plant. [ABSTRACT FROM AUTHOR]

'Achieving sustained environmental health improvements in Freetown through faecal sludge management enterprises' was a partnership project between Freetown City Council (FCC), International Water Association (IWA), and GOAL. This project aimed to improve faecal sludge management (FSM) through public - private partnerships and improved financial flows to ensure viability of businesses. A market assessment was conducted in Freetown which considered demand and supply for FSM services. This paper discusses findings from the household survey which was a key component of the market assessment. While the households felt that they were getting value for money for existing services, they were not satisfied with existing services and hence were willing to pay higher prices for improved services. This highlights the importance of quality service provision in relation to revenue generation. Improved pit emptying services was noted to be of high priority to households. In order to improve pit emptying services the FSM strategy proposed intermediate transfer stations and formation of a Sanitation Unit and Contact Centre within FCC. [ABSTRACT FROM AUTHOR]

The main objective of this study is to develop an economic analysis estimating the solid waste quantities and optimal hauling distance to install transfer stations in Colombia, according to landfill location. This goal is met by using a difference in differences approach (impact evaluation technique), means panel data (random effects), comparative static analysis and mathematical optimization. These methods allowed comparing total production costs between firms with and without transfer stations during three years (2006 to 2008). This study suggests that the use of a transfer station reduces maintenance and operation costs.

Rapid population growth and high rate of urbanization make municipal solid waste management a challenging task for municipalities due to the inadequacy of infrastructural services. Taking this into consideration, this paper proposes an approach for finding economically optimal locations and feasibility demonstration of a municipal solid waste management infrastructure unit, i.e. waste transfer stations. This analytical approach consists of two basic elements: ( i ) a mathematical model to optimize overall cost for municipal solid waste management; and ( ii ) geographical information system tools to create a data inventory for the mathematical model. The novelty of the proposed model includes heterogeneity in data compilation, on-road measurements of distances and strategic allocation of transfer stations. Also, to assess waste load estimation more precisely, analyzing the impacts of heterogeneity in data and on-road distances on model, three distinct cases have been considered. Further, the developed approach has been demonstrated on the city of Nashik, India. The mathematical model for Nashik city is written in a mathematical programming language AMPL and the solutions have been obtained using KNITRO solver. Optimization model selects three best locations out of eight potential locations with the optimum capacity of 200 TPD. Furthermore, the assessment of model's behavior under uncertainty has been performed with a comprehensive sensitivity analysis for further improvements. The integrity of all components in this study produces a generic framework for helping municipal officials and researchers for development of a municipal solid waste management system with transfer stations in an economically optimal manner. [ABSTRACT FROM AUTHOR]

In India, a substantial fraction (∼0.85) of total expenditure on MSW management is spent on collection of waste. Nevertheless, the average waste collection efficiency is about 70% in Indian urban areas. Waste collection efficiency can be increased by utilising staff and collection vehicles effectively with transfer stations (TSs), though choosing best sites (in an economically optimal manner) for TSs siting is a major task. Also, many parameters (e.g., waste-generation rate, running cost of facilities, transportation cost, revenues etc.) in MSW management system are associated with uncertainties. To study the apportionment of these uncertain input parameters into the results, a comprehensive sensitivity analysis has been performed. Furthermore, the effect of interaction among most sensitive parameters is examined through design of experiment. Also, a facility location two stage stochastic model has been proposed to select the best sites for TSs siting, which is basically a framework of facility location problems involving uncertainty. The developed model is applied on the city of Nashik, Maharashtra, India. The model has 9186 constraints and 8152 variables, which has been written in AMPL (a mathematical programming language). KNITRO 5.2 (nonlinearinterior-point trust region optimizer) have been used to solve the developed model. Sensitivity analysis abduces waste generation as the most sensitive kind of parameter followed by the unit transportation cost of waste from source to TSs. Furthermore, multivariate SA identifies the importance of a facility location framework involving uncertainty. [ABSTRACT FROM AUTHOR]

Transfer Stations are facilities dedicated to management, and solid waste transfer of a vehicle to another with greater capacity, which transports them to their place of use or disposal. The main purpose of the research is to represent the location of these kind facilities through a model of mixed integer linear programming, which consider different characteristics of stations such as total capacity and materials recovery. Total costs minimization is the main objective. To do this, we minimize opening fixed costs, transportation costs and operating costs evaluated at the current time through a function of present cost equivalent. [ABSTRACT FROM AUTHOR]

To face the booming passenger flow volumes, the optimization of pedestrian facilities plans and the associated staff assignment plans in the transfer station, including adjusting pedestrian flow routes and adopting different numbers of machines, is an efficient measure to promote transfer connection and avoid passengers congestion in order to enhance the service level. We propose an integrated optimization model based on the simulation model and machine learning method aiming to provide optimal pedestrian facilities plans and the corresponding staff assignment simultaneously. The pedestrian facilities plans ensure the service quality requirement based on three performance indicators, i.e., transfer capacity, transfer average time and level-of-service. The framework, which contains the transfer station simulation model and the Random Forest for obtaining the values of performance indicators, is developed. Random Forest, a machine learning method, trains and learns the samples of indicators and scenario attributes outputted from the simulation model to fit the approximation functions that can evaluate the performance indicators under the given scenarios. As the application, the optimization model uses the approximation functions to obtain performance indicators so that select out the available pedestrian facilities plans for time-varying passenger demands. With the aims of minimizing employment cost and preventing excessive fatigue, the optimization model selects the most suitable pedestrian facilities plans and obtains the corresponding staff assignment plan with the consideration of the workload fairness and rest time under four types of consecutive working time constraints. The experiments of the Xipu station demonstrate that the proposed integrated optimization model can return reasonable pedestrian facilities plans and staff assignment plans for each period in a day. The constraints of consecutive working time can acquire good compromising of reducing labor cost and avoiding overwork, so that the staff assignment plans are acceptable for both station managers and employees. [ABSTRACT FROM AUTHOR]

Abstract: Transfer stations are an important component of modern solid waste management systems. Solid waste management facilities (e.g., landfills) are very attractive to and used by many birds, resulting in a variety of health and safety problems, including disease transmission to humans and increased risk of wildlife–aircraft collisions. In the United States, the Federal Aviation Administration recommends municipal solid waste management facilities (e.g., landfills, transfer stations) not be sited within 8km of an airport. Little information is available regarding the attractiveness of transfer stations to birds or the factors that might influence avian use, particularly on a national scale. The objectives of my study were to: (1) quantify avian use of transfer stations, (2) determine if building design features influence their attractiveness to birds, and (3) determine if other factors (e.g., season, geographic location, operational procedures) influence bird use. Twenty-nine waste transfer facilities and 4 control sites, located in 7 states (representative of various U.S. geographical regions) were studied. Avian abundance and activity was quantified at each facility and control site twice per week for one year. Nuisance bird species commonly observed using transfer stations (e.g., feeding on refuse) included gulls, European starlings, and crows. Patterns of wildlife use at transfer stations varied by season, geographic location, transfer station building design, and on-site management characteristics. Overall, this study demonstrates that wildlife use of transfer stations, particularly by nuisance birds, can be substantial. [Copyright &y& Elsevier]

The collection, transfer and transport of waste are basic activities of waste management systems all over the world. These activities all use energy and fuels, primarily of fossil origin. Electricity and fuel consumptions of the individual processes were reviewed and greenhouse gases (GHG) emissions were quantified. The emission factors were assigned a global warming potential (GWP) and aggregated into global warming factors (GWFs), which express the potential contribution to global warming from collection, transport and transfer of 1 tonne of wet waste. Six examples involving collection, transfer and transport of waste were assessed in terms of GHG emissions, including both provision and use of energy. (GHG emissions related to production, maintenance and disposal of vehicles, equipment, infrastructure and buildings were excluded.) The estimated GWFs varied from 9.4 to 368 kg CO2-equivalent (kg CO2-eq.) per tonne of waste, depending on method of collection, capacity and choice of transport equipment, and travel distances. The GHG emissions can be reduced primarily by avoiding transport of waste in private cars and by optimization of long distance transport, for example, considering transport by rail and waterways. [ABSTRACT FROM AUTHOR]

This paper investigates the locational patterns of facilities that deal with municipal solid waste. A mixed-integer linear programming problem is set up to optimize the locations of landfills and garbage transfer stations in the province of Alberta. The solutions are analyzed with respect to their sensitivity to changes in the metric and the number of facilities opened. [ABSTRACT FROM AUTHOR]

The pollutants emission during the process of municipal solid waste management (MSWM) is of great concern due to its hazardous effect on the environment and living organisms. An assessment of the air quality of MSWM sites was made after having 16 repetitive visits at solid waste disposal sites and transfer stations of Lahore during wet and dry seasons. Pollution parameters such as fine particulate matter (PM2.5) and greenhouse gases (GHG) were measured along with meteorological parameters. PM2.5 measurement was made by using particle counter Dylos and TSI's Dust Trak. Both of these instruments were positioned simultaneously at the source site and downwind (50 m). CH4 and meteorological parameters were measured by Aeroqual 500 series, while the Extech CO220 monitor was used to measure CO2 concentration. An assessment of air quality showed the levels of their mean values as CH4 and CO2 ranged between 1.5–13.7 ppm and 443.4–515.7 ppm, respectively. The PM2.5 ranged between 127.1 and 307.1 µg/m3 at sources and 172.3 and 403.8 µg/m3 downwind (50 m). GHG showed lower levels than the proposed limit value, which could not cause any health issues, while PM2.5 was 6–10 times higher than the Pak-EPA established standards. Higher pollutant concentration was recorded in the dry season than the wet season. Regression analysis was performed to predict correlation of PM2.5 with GHG and meteorological parameters. GHG as well as meteorological parameters also exhibited a correlation with PM2.5. It was estimated that the ambient air of such sites is not safe for public health. So, it is necessary to use safe practices for MSWM and its emission control to prevent nearby communities and the environment. [ABSTRACT FROM AUTHOR]

Life-cycle assessment concepts and methods are currently being applied to evaluate integrated municipal solid waste management strategies throughout the world. The Research Triangle Institute and the U.S. Environmental Protection Agency are working to develop a computer-based decision support tool to evaluate integrated municipal solid waste management strategies in the United States. The waste management unit processes included in this tool are waste collection, transfer stations, recovery, compost, combustion, and landfill. Additional unit processes included are electrical energy production, transportation, and remanufacturing. The process models include methodologies for environmental and cost analysis. The environmental methodology calculates life cycle inventory type data for the different unit processes. The cost methodology calculates annualized construction and equipment capital costs and operating costs per ton processed at the facility. The resulting environmental and cost parameters are allocated to individual components of the waste stream by process specific allocation methodologies. All of this information is implemented into the decision support tool to provide a life-cycle management evaluation of integrated municipal solid waste management strategies. [ABSTRACT FROM AUTHOR]

• Assessment of existing collection and transportation techniques for MSW. • Selection of appropriate technique for an urban center. • Feasibility study to have transfer stations in MSW management system. • Importance of mathematical modeling to develop an efficient MSW C&T system. Collection and transportation (C&T) of municipal solid waste (MSW) is a major contributor to the overall cost, air emissions, social indignation, and fuel consumption in the entire management system. Different techniques are practiced or proposed in urban centers globally to develop an economically feasible, environmentally sustainable, socially convenient, and technologically updated C&T. Unfortunately, little research has been carried out for emphasizing salient features of diverse C&T techniques to draw any firm conclusion on their suitability for the specific urban area. Therefore, this short communication describes different C&T techniques with recommendations on their suitability for specific urban areas in developing or developed countries and plausible mathematical or computational modeling approaches to make them more efficient. This study will facilitate municipal officials to decide an appropriate C&T technique for their respective MSW management system. This article can further be used as a reference text for stakeholders to evaluate their C&T technique mathematically. [ABSTRACT FROM AUTHOR]